1. Field of the Invention
The present invention relates to placement of component parts in a factory or the like, and more particularly to parts placement calculation for automatically calculating locations where such parts are to be placed.
2. Description of Related Art
In factories or the like, component parts which have been processed in one production process are sometimes temporarily stored in a parts storage before being used in a subsequent process. For example, in the case of lot production using a press or the like in automobile manufacturing factories, it is necessary to temporarily store relatively large parts such as body panels in a limited space. In addition, numerous types of other parts must also be stored. Therefore, appropriate parts placement, being the determination of storage locations for components and other parts, should be performed.
Conventionally, in order to determine parts placing locations, a person such as responsible for placement of parts designs the placement design by drawing the parts placing location of each parts on a CAD system, taking consideration of the parts placing area in the parts storage or the like based on his/her own experience.
In such conventional placement design performed by a parts manager on a CAD system as described above, calculations are complicated and can be enormous when a great number of parts are to be placed in a limited space. Thus, the conventional placement design requires a very great calculation time, and, due to the complexity of the calculations, is simply incapable of giving sufficient consideration to the physical distribution efficiency associated with parts transportation.
The present invention advantageously provides a parts placement calculation system, a parts placement calculation method, a parts placement calculation program, a recording medium which records a parts placement calculation program, and a parts placement support system, capable of designing parts placement taking the physical distribution efficiency and the area efficiency into consideration, even when a wide variety of parts must be located in a limited space.
The present invention was conceived in view of the aforementioned problems of the related art and provides a parts placement calculation system for distributing and placing parts of a plurality of types in a plurality of stores within a parts storage based on a parts point value for each type of parts and a store point value for each store with regard to each type of parts, the system comprising parts selection means for selecting a parts with the highest parts point value from a list of parts to be placed, store selection means for selecting a store with the highest store point value from a list of placement possible stores regarding the selected parts, and placement determination means for determining whether or not the selected parts can be placed in the selected store, based on a predetermined constraint condition for placing the selected parts in the selected store, wherein, when the placement determination means determines that the selected parts cannot be placed in the selected store, the selected store is deleted from the list of placement possible stores and then the store selection means is activated again, and, when the placement determination means determines that the selected parts can be placed in the selected store, a parts area for placing the selected parts in the store is determined, and the selected parts is deleted from the list of parts to be placed, and then the parts selection means is activated again.
With the above configuration, meaning of parts includes types of parts and quantity of parts which are placed. Parts placement calculation can be automatically performed by the parts placement calculation system. Therefore, compared to conventional parts placement calculation which typically requires a calculation time on the order of two to three weeks, the calculation time required for the present system is significantly reduced to several tens of minutes, which drastically reduces the possibility of calculation errors and placement impossibility. Further, conventionally, when a large number of types of parts which are relatively large are to be located within a limited space, placement is actually performed taking only the placing area into consideration. Even in such a situation, the present system allows parts placement which takes not only the area efficiency but also the parts transportation efficiency into consideration.
Preferably, the constraint condition in the placement determination means is that selected parts do not overlap a parts area which is already positioned and an obstacle, and that an area sufficient for placing selected parts are provided.
Further, in order to achieve the above advantage, the present invention provides a parts placement calculation system for distributing and placing parts of a plurality of types in a plurality of stores within a parts storage based on a parts point value for each type of parts and a store point value for each store with regard to each type of parts, the system comprising placement possible store set extraction means for removing a store in which placement is not possible based on a predetermined constraint condition for placing each parts from a store list associated with each parts, parts selection means for selecting a parts with the highest parts point value from a list of parts to be placed, and store selection means for selecting a store with the highest store point value from a list of placement possible stores regarding the selected parts, wherein, after the placement possible store set extraction means is executed, parts are selected by the parts selection means, a store for the selected parts is selected by the store selection means, and a parts area for placing the selected parts is determined in the selected store, and then after deleting the selected parts from the list of parts to be placed, the placement possible store set extraction means is executed again.
With the above configuration, it is possible to consider a constraint condition regarding a plurality of parts, including a constraint condition that a plurality of parts are placed in the same store, for example. Furthermore, placement calculation time can be further reduced because it is possible to remove a store in which placement is not possible from a store list prior to activation of the store selection means.
Preferably, the constraint condition in the placement possible store set extraction means is that a selected parts do not overlap a parts area which is already positioned or an obstacle, and that an area sufficient for placing a selected parts are provided, and also that when it is instructed to place a plurality of arbitrary parts in a same store, all of the plurality of arbitrary parts have an identical store list.
Preferably, the parts point value is obtained by adding a priority and an area difference of corresponding parts with a predetermined weighting coefficient multiplied therewith. The priority is a function of the frequency of carrying in and out the corresponding parts and the area difference is a function of a difference between the largest value and the smallest value of placing areas in stores for placing the corresponding parts, the placing areas being different for different stores due to a predetermined placing condition. The store point value is obtained by adding a transportation distance point value and an area point value of a corresponding store with a predetermined weighting coefficient multiplied therewith. The transportation distance point value is a function of a transportation distance for carrying parts in and out of the corresponding store and the area point value is a function of a placing area which depends on a predetermined placing condition when placing parts in the corresponding store.
With the above configuration, it is further possible to perform placement in consideration of both the physical distribution efficiency and the area efficiency.
Preferably, the placing condition regarding the parts point value and the store point value is that only pallets containing the same types of parts are placed in the same pallet placement line which is in the lift traveling direction in the store, that pallet placement lines for the same types of parts are located adjacent to each other, and that pallets for the same type of parts are placed in the same store.
With the above configuration, because parts which are the same as the parts placed in the further area of the store seen from the passage is placed closer to the passage, parts can be easily transported using a lift. Further, because the same parts are placed collectively in the same store, parts transportation and confirmation is made more convenient.
Preferably, the above parts placement calculation system further comprises external input means for selecting a weighting coefficient of the parts point value and the store point value from a plurality of predetermined values and inputting the selected value.
Preferably, the above parts placement calculation system further comprises dividing means for dividing an interior of the parts storage into a plurality of rectangular stores, passages extending in parallel to outer peripheries of each store, and obstacles. Parts of the same type are contained in the same pallet, and each pallet is transported by a lift, which, when traveling along the passages and reaches a location near the store, turns substantially the vertical direction with regard to a passage traveling direction and advances substantially straight to enter the store for carrying each pallet in and out. The system further comprises coordinate system generating means for generating a plan coordinate system which is converted such that, assuming a lift traveling direction facing the passage within a store as a lift passage direction, a plurality of stores are rotated so that the lift passage directions thereof are oriented in a predetermined direction.
With the above configuration, calculation time can be further reduced by use of a plan coordinate system which obviates the need for complicated placement calculations.
Preferably, parts to be placed are divided into a plurality of groups, from which a certain group is selected, and after determining a parts area for placing all the parts included in the selected group, the determined parts areas are fixed, and then another group of the remaining groups is selected and parts areas for placing all the parts included in the selected group are determined. Then, the above procedure is repeated.
With the above configuration, because the parts placement is carried out step by step, situational changes during the parts placement process can be easily accommodated, and desined parts can be preferentially placed.
Preferably, the above parts placement calculation system further comprises segment positioning means for, after determination of a parts area, positioning a segment having a size corresponding to the pallet size with an extra space and provided corresponding to each pallet within the parts area. The segment positioning means selects an arbitrary segment from a list of segments to be positioned within the parts area, and positions the selected segment at the furthest point, seen from the passages, of a positioning possible portion except a segment already positioned and the obstacle, in an arbitrary single line in which a segment can be positioned, and the selected segment is deleted from the list of segments, and the above procedure is repeated after selecting another arbitrary segment from the list of segments.
With the above configuration, by setting the desired size segment, it is possible to secure a desired gap between pallets to be placed.
(2) Further, in order to achieve the above advantage, the present invention provides a parts placement calculation method for distributing and placing parts of a plurality of types in a plurality of stores within a parts storage based on a parts point value set for each type of parts and a store point value set for each store with regard to each type of parts, the method comprising a step in which a parts selection means selects parts with the highest parts point value from a list of parts to be placed, a step in which a store selection means selects a store with the highest store point value from a list of placement possible stores regarding the selected parts, and a step in which a placement determination means determines whether or not the selected parts can be placed in the selected store, based on a predetermined constraint condition for placing the selected parts in the selected store. In the above method, when the placement determination means determines that the selected parts cannot be placed in the selected store, the selected store is deleted from the list of placement possible stores and then the store selection means is again activated, and, when the placement determination means determines that the selected parts can be placed in the selected store, a parts area for placing the selected parts in the store is determined, the selected parts are deleted from the list of parts to be placed, and then the parts selection means is activated again.
With the above configuration, by causing a parts placement calculation system to perform the above method, it is possible to significantly reduce the calculation time to several tens of minutes, compared to conventional parts placement calculations which require a large calculation time on the order of two to three weeks, and it is also possible to reduce drastically the possibility of calculation errors and placement fault. Further, conventionally, when a large number parts types of a relatively large physical size are to be placed in a limited placing space, placement is actually performed taking only the placing area into consideration. Even in such a situation, present method allows parts placement which considers parts transportation efficiency as well as area efficiency.
Preferably, the constraint condition in the placement determination means is that selected parts do not overlap a parts area which is already positioned or an obstacle, and that an area sufficient for placing a selected parts are provided.
Further, in order to achieve the above advantage, the present invention provides a parts placement calculation method for distributing and placing parts of a plurality of types in a plurality of stores within a parts storage based on a parts point value set for each type of parts and a store point value set for each store with regard to each type of parts, the method comprising a step in which a placement possible store set extraction means removes a store in which placement is not possible based on a predetermined constraint condition for placing each parts from a store list associated with each parts, a step in which a parts selection means selects parts with the highest parts point value from a list of parts to be placed, and a step in which a store selection means selects a store with the highest store point value from a list of placement possible stores regarding the selected parts. In the above step, after the placement possible store set extraction means is executed, parts is selected by the parts selection means, a store for the selected parts is selected by the store selection means, and a parts area for placing the selected parts is determined in the selected store, and then after deleting the selected parts from the list of parts to be placed, the placement possible store set extraction means is executed again.
With the above configuration, it is possible to consider a constraint condition regarding a plurality of parts, including a constraint condition that a plurality of parts are placed in the same store, for example. Further, because it is possible to remove a store in which placement is not possible from a store list prior to activation of the store selection means, the placement calculation time is further reduced.
Preferably, the constraint condition in the placement possible store set extraction means is that selected parts do not overlap a parts area which is already positioned or an obstacle, and that an area sufficient for placing selected parts are provided, and also that when instructed to place a plurality of arbitrary parts in a same store, all of the plurality of arbitrary parts must have an identical store list.
Preferably, the parts point value is obtained by adding a priority and an area difference of corresponding parts with a predetermined weighting coefficient multiplied therewith. The priority is a function of the frequency of carrying the corresponding parts in and out, and the area difference is a function of a difference between the largest value and the smallest value of placing areas in stores for placing the corresponding parts, the placing areas being different for different stores due to a predetermined placing condition. The store point value is obtained by adding a transportation distance point value and an area point value of a corresponding store with a predetermined weighting coefficient multiplied therewith, and the transportation distance point value is a function of a transportation distance for carrying parts in and out of the corresponding store and the area point value is a function of a placing area which depends on a predetermined placing condition when placing parts in the corresponding store.
With the above configuration, it is further possible to perform placement while taking into consideration both the physical distribution efficiency and the area efficiency.
Preferably, the placing condition regarding the parts point value and the store point value is that only pallets containing the same types of parts are placed in the same pallet placement line which is in the lift traveling direction in the store, that pallet placement lines for the same type of parts are located adjacent to each other, and that pallets for the same type of parts are placed in the same store.
With the above configuration, because parts which are the same as the parts placed in the further area seen from the passage is placed closer to the passage, parts can be easily transported using a lift. Further, because the same parts are placed collectively in the same store, convenience of parts transportation and confirmation can be enhanced.
Preferably, the above parts placement calculation method further comprises a step in which external input means selects a weighting coefficient of the parts point value and of the store point value from a plurality of predetermined values and inputs the selected value.
Preferably, the above parts placement calculation method further comprises a step in which dividing means divides an interior of the parts storage into a plurality of rectangular stores, passages extending in parallel to outer peripheries of each store, and obstacles, and parts of the same type are contained in the same pallet, and each pallet is transported by a lift, which, when traveling along the passages and reaches a location near the store, turns substantially the vertical direction with regard to a passage traveling direction and advances substantially straight to enter the store for transporting each pallet in and out. The method further comprises a step in which coordinate system generating means generates a plan coordinate system which is converted such that, assuming a lift traveling direction facing the passage within a store as a lift passage direction, a plurality of stores are rotated so that the lift passage directions thereof are oriented in a predetermined direction.
With the above configuration, because complication of a placement calculation can be prevented by use of a plan coordinate system, the calculation time can be further reduced.
Preferably, parts to be placed are divided into a plurality of groups, from which a certain group is selected, and after determining a parts area for placing all the parts included in the selected group, the determined parts areas are fixed, and then another group of the remaining groups is selected and a parts area for placing all the parts included in the selected group are determined. Then, the above procedure is repeated.
With the above configuration, because the parts placement is carried out step by step, changes in the situation in the middle of the parts placement can be easily accommodated such that desired parts are preferentially placed.
Preferably, the above parts placement calculation method further comprises a step in which a segment positioning means, after determination of a parts area, positions a segment having a size corresponding to the pallet size with an extra space and provided corresponding to each pallet, within the parts area. In the above method, the segment positioning means selects an arbitrary segment from a list of segments to be positioned within the parts area, and positions the selected segment at the furthest point, seen from the passages, of a positioning possible portion except a segment already positioned and the obstacle, in arbitrary one line in which a segment can be positioned, and the selected segment is deleted from the list of segments and the above procedure is repeated after selecting another arbitrary segment from the list of segments.
By setting the desired size segment with the above configuration, it is possible to secure a desired gap between pallets to be placed.
(3) Still further, in order to achieve the above advantage, the present invention provides a parts placement calculation program which causes a computer to carry out a parts placement calculation for distributing and placing parts of a plurality of types in a plurality of stores within a parts storage based on a parts point value set for each type of parts and a store point value set for each store with regard to each type of parts, the parts placement calculation program causing the computer to function as parts selection means for selecting parts with the highest parts point value from a list of parts to be placed, store selection means for selecting a store with the highest store point value from a list of placement possible stores regarding the selected parts, and placement determination means for determining whether or not the selected parts can be placed in the selected store, based on a predetermined constraint condition for placing the selected parts in the selected store, wherein, when the placement determination means determines that the selected parts cannot be placed in the selected store, the selected store is deleted from the list of placement possible stores and then the store selection means is activated again, and, when the placement determination means determines that the selected parts can be placed in the selected store, a parts area for placing the selected parts in the store is determined, the selected parts are deleted from the list of parts to be placed, and the parts selection means is the reactivated.
With the above configuration, a parts placement calculation can be automated and performed by a computer. This makes it possible to significantly reduce the calculation time, down to the order of several tens of minutes, compared to the calculation time on the order of two to three weeks required by conventional methods. Calculation error and associated placement impossibility are meanwhile reduced. Further, while conventionally, when a large number of types of parts having a relatively large physical size are to be placed in a limited placing space, placement is actually performed taking only the placing area into consideration, the present system allows parts placement which takes not only the area efficiency but also the parts transportation efficiency into consideration.
Preferably, the constraint condition in the placement determination means is that selected parts do not overlap a parts area which is already positioned or an obstacle, and that an area sufficient for placing a selected parts are provided.
Further, in order to achieve the above advantage, the present invention provides a parts placement calculation program which causes a computer to carry out a parts placement calculation for distributing and placing parts of a plurality of types in a plurality of stores within a parts storage based on a parts point value set for each type of parts and a store point value set for each store with regard to each type of parts, the parts placement calculation program causing the computer to function as placement possible store set extraction means for removing a store in which placement is not possible based on a predetermined constraint condition for placing each parts from a store list associated with each parts, parts selection means for selecting parts with the highest parts point value from a list of parts to be placed, and store selection means for selecting a store with the highest store point value from a list of placement possible stores regarding the selected parts, wherein, after the placement possible store set extraction means is executed, parts are selected by the parts selection means, a store for the selected parts is selected by the store selection means, and a parts area for placing the selected parts is determined in the selected store, and then after deleting the selected parts from the list of parts to be placed, the placement possible store set extraction means is again executed.
With the above configuration, it is possible to consider a constraint condition regarding a plurality of parts, including a constraint condition that a plurality of parts must be placed in the same store, for example. Further, because it is possible to remove a store in which placement is not possible from a store list prior to activation of the store selection means, the placement calculation time can be further reduced.
Preferably, the constraint condition in the placement possible store set extraction means is that selected parts do not overlap a parts area which is already positioned and an obstacle, and that an area sufficient for placing selected parts are provided, and also that when it is instructed to place a plurality of arbitrary parts in a single store, all of the plurality of arbitrary parts must have an identical store list.
Preferably, the parts point value is obtained by adding a priority and an area difference of corresponding parts with a predetermined weighting coefficient multiplied therewith, and the priority is a function of the frequency at which the corresponding parts is transported in and out, and the area difference is a function of a difference between the largest value and the smallest value of placing areas in stores for placing the corresponding parts, the placing areas being different for different stores due to a predetermined placing condition. The store point value is obtained by adding a transportation distance point value and an area point value of a corresponding store with a predetermined weighting coefficient multiplied therewith, and the transportation distance point value is a function of a transportation distance for carrying parts in and out of the corresponding store and the area point value is a function of a placing area which depends on a predetermined placing condition when placing parts in the corresponding store.
With the above configuration, it is further possible to perform placement which takes into consideration both the physical distribution efficiency and the area efficiency.
Preferably, the placing condition regarding the parts point value and the store point value is that only pallets containing the same types of parts are placed in the same pallet placement line which is in the lift traveling direction in the store, that pallet placement lines for the same types of parts are located adjacent to each other, and that pallets for the same type of parts are placed in the same store.
With the above configuration, because parts which is the same as the parts placed in the further area seen from the passage is placed closer to the passage, transportation in and out of parts using a lift can be performed easily. Further, because the same parts are placed collectively in the same store, parts transportation and confirmation can be performed conveniently.
Preferably, the above parts placement calculation program further causes a computer to function as external input means for selecting a weighting coefficient of the parts point value and the store point value from a plurality of predetermined values and inputs the selected value.
Preferably, the above parts placement calculation program further causes a computer to function as dividing means for dividing an interior of the parts storage into a plurality of rectangular stores, passages extending in parallel to outer peripheries of each store, and an obstacle. Parts of the same type are contained in the same pallet, and each pallet is transported by a lift, which, when traveling along the passages and reaches near the store, turns to a substantially vertical direction with regard to a passage traveling direction and advances substantially straight to enter the store for carrying each pallet in and out. The above program further causes a computer to function as coordinate system generating means for generating a plan coordinate system which is converted such that, assuming a lift traveling direction facing the passage within a store as a lift passage direction, a plurality of stores are rotated so that the lift passage directions thereof are oriented in a predetermined direction.
With the above configuration, because complication of a placement calculation can be prevented through use of a plan coordinate system, the calculation time can be further reduced.
Preferably, parts to be placed are divided into a plurality of groups, from which a certain group is selected, and, after a parts area for placing all the parts included in the selected group is determined, the determined parts areas are fixed, and then another group of the remaining groups is selected and a parts area for placing all the parts included in the selected group is determined. Then, the above procedure is repeated as appropriate.
With the above configuration, because the parts placement is carried out step by step, changes in the situation can be readily accommodated, even in the middle of the parts placement process, such that desired parts can be preferentially placed.
Preferably, the above parts placement calculation program further causes a computer to function as segment positioning means for, after determination of a parts area, positioning a segment having a size corresponding to the pallet size with an extra space and provided corresponding to each pallet, within the parts area, wherein the segment positioning means selects an arbitrary segment from a list of segments to be positioned within the parts area, and positions the selected segment at the point furthest from the passages of a positioning possible portion, except where a segment or obstacle is already positioned, along an arbitrary one line in which a segment can be positioned, and the selected segment is deleted from the list of segments and the above procedure is repeated after selecting another arbitrary segment from the list of segments.
With the above configuration, by setting the desired size segment, it is possible to secure a desired gap between pallets to be placed.
(4) Further, in order to achieve the above advantage, a parts placement calculation program according to the present invention may be recorded on a computer readable recording medium. When this recording medium is read by a computer, it is possible to cause the computer to perform a parts placement calculation for placing parts. A recording medium may be, for example, a disc medium such as a CD-ROM and DVD-ROM.
(5) Still further, the present invention provides a parts placement support system including the above-described parts placement calculation system comprising an integrated database for managing data which is necessary for parts placement, and a layout changing system for retrieving layout information from the integrated database and outputting the layout information after the layout information has been corrected, when the layout within a parts storage is changed, wherein the parts placement calculation system performs a parts placement calculation based on the data managed by the integrated database.